The present invention relates to a memory card casing that includes metal covers adapted to be easily and firmly assembled to two sides of a plastic framework that holds a circuit board thereto.
A memory card typically includes a flat framework made of plastic material for holding a circuit board and the circuit elements thereof. For the memory card to be thin and rigid as required, metal covers are further mounted onto upper and lower surfaces of the plastic framework. That is, the plastic framework and the two metal covers together form a casing of a general memory card.
Currently, there are generally two ways to combine the metal covers with the plastic framework. In the first way, the plastic framework is applied at two sides with glue to bond the very thin metal covers thereto. In the second way, the very thin metal covers formed through punching are put into a mold in a plastic injecting machine, so that each metal cover is coated at outer edges with injected plastic material to form a half frame ready for supersonic machining.
By superposing two opposed half frames of the metal covers and combining them together through supersonic welding, a memory card casing is formed.
Either the first or the second way of forming a memory card casing necessitates the use of a bonding machine or supersonic-welding machine and therefore requires higher manufacturing cost. Moreover, considerable time is needed to complete the mechanical assembling of the memory card casing and the production efficiency thereof is therefore low.
It is a primary object of the present invention to provide a novel memory card casing including components that could be easily and quickly assembled without using any machine.
In an aspect of the present invention, the memory card casing includes a plastic framework, and an upper and a lower metal cover adapted to respectively press onto upper and lower sides of the plastic framework. The upper and the lower metal covers are correspondingly provided along more than one edge with upper and lower wall portions, respectively, that perpendicularly extend toward each other. A plurality of spaced fastening means, each including a first fastening plate and a second fastening plate, are provided on the upper and the lower wall portions. Each of the first fastening plates defines a tongue and each of the second fastening plates defines a retaining hole. A space is defined between any two adjacent fastening means on the upper and the lower wall portions, such that a pair of two vertically corresponded spaces together form a closed hole when the upper and the lower metal covers are closed onto two sides of the plastic framework. The plastic framework is adapted to enclose the three edges of the upper and the lower metal covers provided with the wall portions. The plastic framework is provided on inner wall surfaces with spaced retaining means corresponding to the spaces at where the closed holes are to be formed. Each of the retaining means includes a narrowed neck portion perpendicularly projected from the inner wall surface of the plastic framework and an expanded head portion integrally connected to a front of the neck portion. Whereby when the upper and the lower metal covers are assembled to the plastic framework by pressing them onto upper and lower sides of the plastic framework, the first fastening plates and the second fastening plates of the fastening means firmly couple with one another with the tongues extended through the retaining holes, and the neck portions of the retaining means on the plastic framework are confined in the closed holes formed from the spaces on the upper and the lower metal covers, causing the plastic framework and the upper and the lower metal covers to firmly connect to one another and form a unit.
In another aspect of the present invention, the first fastening plate of each fastening means defines a holed inward recess and a tongue upward and outward extended from the inward recess, and the second fastening plate defines a retaining hole therein. When the upper and the lower metal covers are closed onto each other, the second fastening plates are located in the inward recesses of the first fastening plates with the tongues extended through the retaining holes to hold the second fastening plates to the first fastening plates and thereby prevent the upper metal cover from separating from or moving sideward relative to the lower metal cover.
In a further aspect of the present invention, the first fastening plate of each fastening means defines a holed inward recess, and the second fastening plate defines a downward extended tongue. When the upper and the lower metal covers are closed onto each other, the second fastening plates are located in the inward recesses of the first fastening plates with the tongues extended through the holed inward recesses to hold the second fastening plates to the first fastening plates and thereby prevent the upper metal cover from separating from or moving sideward relative to the lower metal cover.
In a still further aspect of the present invention, the upper or the lower wall portion that has the second fastening plate spaced thereon is provided with stoppers preferably close to the second fastening plates. The stoppers are so shaped that they perpendicularly extend from the upper or the lower wall portion to fitly abut on an inner wall surface of the lower or the upper wall portion opposite to them when the upper and the lower metal covers are closed to each other. Whereby the stoppers are adapted to work with the tongues of the first fastening plates on the opposite wall portion to produce an outward and an inward force, respectively, to restrict the upper metal cover from moving inward or outward relative to the lower metal covers.